J. Tamaoki et al., AIRWAY HYPERRESPONSIVENESS TO HISTAMINE IN MYCOPLASMAL INFECTION - ROLE OF HISTAMINE N-METHYLTRANSFERASE, European journal of pharmacology, 347(2-3), 1998, pp. 257-260
To elucidate the modulatory role of histamine-degrading enzymes in air
way constrictor responses in mycoplasmal infection, we studied hamster
tracheal segments under isometric conditions in vitro. Nasal inoculat
ion with Mycoplasma pneumoniae potentiated the contractile responses t
o histamine but not to methacholine. Pretreatment of tissues with the
histamine N-methyltransferase inhibitor SKF 91488 abolished the infect
ion-induced potentiation, whereas, the diamine oxidase inhibitor amino
guanidine had no effect. The histamine N-methyltransferase but not dia
mine oxidase activity in tracheal tissues was decreased in infected an
imals. These results suggest that M. pneumoniae causes airway hyperres
ponsiveness to histamine probably through a reduction of endogenous hi
stamine N-methyltransferase activity. (C) 1998 Elsevier Science B.V.